Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities
Net loss	$ (43,485)	$ (98,700)
Adjustments to reconcile net loss to net cash provided by operating activities:
Loss on disposal of oil and gas properties		35
Accretion of asset retirement obligations	139	180
Depletion, depreciation, and amortization	56,818	51,995
Stock-based compensation	1,629	448
Deferred taxes	(29,191)	19,588
Gain on disposal of bonds		(28,480)
Losses on derivative financial instruments	14,080	8,672
Settlements of derivative financial instruments	5,207	29,790
Impairment of oil and gas properties	33,413	35,570
Non-cash interest expense	4,571	7,581
Gain on warrants	(3,088)	(568)
Changes in operating assets and liabilities:
Accounts receivable	(6,851)	234
Prepaid expenses and other assets	833	(1,856)
Accounts payable and accrued expenses	9,371	(220)
Net cash provided by operating activities	43,446	24,269
Cash flows from investing activities
Acquisition of oil and gas properties	(113,726)	(4,340)
Development of oil and gas properties	(81,875)	(39,382)
Proceeds from sales of oil and gas properties		16,174
Purchases of other property and equipment	(13,142)	(233)
Net cash used in investing activities	(208,743)	(27,781)
Cash flows from financing activities
Proceeds from borrowings and related party borrowings	123,968	72,063
Payments on borrowings and related party borrowings	(34,017)	(134,697)
Proceeds from sale of common stock, net of offering costs		72,807
Proceeds from sale of preferred stock	77,800
Cost to issue equity	(3,296)
Payments of debt issuance costs	(2,685)	(4,912)
Changes in other notes payable	(3)	(3)
Net cash provided by financing activities	161,767	5,258
(Decrease) increase in cash and cash equivalents	(3,530)	1,746
Cash and cash equivalents, beginning of the period	6,068	4,322
Cash and cash equivalents, end of the period	2,538	6,068
Supplemental information:
Cash paid for taxes	2,474	1,820
Cash paid for interest expense	20,389	23,691
Non-cash investing and financing activities:
Asset retirement obligation	2,827	(24)
Increase in liabilities for capital expenditures	8,379	2,666
Cost to issue equity included in accounts payable		1,000
Preferred Stock
Non-cash investing and financing activities:
Stock issued for asset/business acquisition	$ 10,795
Common Stock
Non-cash investing and financing activities:
Stock issued for asset/business acquisition		$ 5,500